Fiber glass tank



July 2, 1963 G. A. BALcoM ETAL 3,095,993

FIBER GLASS TANK Filed Nov. 5, 195s 34 /7 -1- j /0 @'grNVENTORS 3,095,993 FIBER GLASS TANK George A. Balcom, Cleveland, and Ralph L. Archhold,

Euclid, Ohio, assignors to White Sewing Machine Corporation, Lakewood, Ohio, a corporation of Delaware Filed Nov. 5, 1958, Ser. No. 772,026 3 Claims. (Cl. 2211-5) Our invention relates to ber glass tanks and more particularly to a tank made of sections having cylindrical arent portions and the method by which said cylindrical porr Patented July 2, 1963 ing to the method and apparatus disclosed in U.S. Patent No. 3,012,922 to Arthur I. Wiltshire of December 12, 1961, owned by the assignee of the instant application.

After the tubular section 11 is completed it is formed to provide a wall thickness of about three-tenths lof an inch for a tank about seven inches in diameter. The end portions `of the tube are then undercut. It will be understood that in the drawings the showing of the wall thickness is not to scale but for clarity illustration of the thickness of `the parts and the changes in dimensions by machining have been exaggerated.

The undercut for each end of the tubular structure 11 is preferably about .020 inch. The undercut from the bottom of the tank, as shown in FIG. 1, extends from the extreme end of the tank to the plane indicated at 12.

, The undercutting may be accomplished in a lathe and the end caps for 'the tank include cylindrical portions which are shaped to facilitate the assembly of :the body and end caps. The invention also provides end cap and body construction suited for use with novel apparatus for effecting the rm attachment of the tank parts to each other.

It is among the objects of our invention to provide a ber glass tank having a tubular body wherein each end of the tubular body is undercut at its inner diameter and wherein the end caps for the tank are formed to telescope within said undercut portions of the body and wherein the end caps and undercut body portion lare shaped to provide an annular locking ring securely xing the end caps to the body.

It is a further object of our invention to provide an apparatus for forming the annular locking ring of the preceding object.

It is a further object of our invention to provide a method of forming telescopic portions of a tank body and end caps to provide an annular chamber which is undercutting tool is followed by a grooving cutter which grooves the undercut portion of the tube to the plane indicated at 13. The grooves may be parallel or spiral and are about .005 inch deep. The groove vdimension is exaggerated in the drawings.

The tank is provided with a tcp end cap 14 and a bottom end cap 15. The end cap-s are made in matched metal molds and are preferably proportioned Ito pro vide a thickness of about one-eighth of `an inch for a seven inch diameter tank. Each of the end caps 14 and 15 is formed to provide cylindrical portions which are lled with a bonding material and wherein the bonding material is cured under pressure and is fixed to portions of .the tank body and portions of the end caps so as -to provide a structure which will withstand high uid pressures.

Further objects and advantages relating to reduction in cost of tank manufacture, long life and ruggedness in construction will appear from the following description and the appended drawings wherein:

FIG. 1 is Va sectional elevation of a tank having a body and end caps assembled according to our invention;

FIG. 2 is a sectional view of the tank taken along the plane as indicated at 2-2 of FIG. 1 and wherein the tank is fitted with means for introducing the bonding material;

FIG. 3 is a transverse sectional view similar to the view of FIG. 2 and wherein the tank is tted with means for retaining the bonding material under pressure dining the curing of the tank; and

FIG. 4 is an enlarged sectional view of the joint between lthe tank body and an end cap with the bonding material cured in position.

The tank assembly indicated in its entirety in FIG. 1 as at 10 includes a tubular section 11. This tubular section is preferably made from resin impregnated ber glass wherein 4the ber glass is characterized by chopped bers about two inches long compressed to form a dense mat. The spaces between the mat bers are lled with resin and the tube 11 in its cured form is uid-tight, well suited to withstand domestic water system pressures. Numerous methods of forming tubular ber glass articles may be employed and preferably the tube is made accordtelescoped within the undercut section of the tubular body 11. The cylindrical portions of each of the end caps are machined to have a diameter in the portions indicated at 16 and 17 about .010 inch greater than the internal diameter of the undercut portion. This provides a tight interference t in areas 16 and 17. The yexterior of each of the end caps is then provided with an annular lchannel having an axial extent as indicated at 18 in FIG. 1. The annular channel or groove is indicated at 19. The bottom of the annular groove 19 is preferably provided with grooves about .005 inch deep. The extreme end portions of the caps 14 and 1S are each chamfered as indicated at 20 to facilitate the telescoping of the end caps within the tubular body 11. The end cap 14 prior to being tted within the tube 11 is provided with a metal outlet fitting 21 which is cemented into the end cap 14. As illustrated in FIG. l the interior threads of the tting 21 are adapted to receive threads on a valve body 22 yand an O-ring 23 may be pressed between the end face of the end cap 14 and the flange of the valve body.

n After the end caps 14 and 15 and the tubular body 11 are machined they are assembled as illustrated in FIG. 1. Openings are provided at each end of the tank body as indicated at 25, 26, 27 and 28 and each end of the tank is then tted with a clamping memberrSllfwhich is in the form of a metal band with the free ends of the band bolted to each other as at 31. A ller plug 32 is welded to the band 30 and is aligned through gasket 32a with hole 2S in the wall of the tubular member 11.

A container 33 is lled with a bonding mixture -indicated at 34 which consists of two parts of powdered asbestos and one part of a polyester resin, preferably a resin known as Hetron No. 31, and a catalyst which is about one percent by weight of methyl ethyl ketone peroxide. The catalyst is also known -in the trade as MEK. The container 33 is tted with an air inlet line 35 and air under pressure is applied to the surface of the bonding mixture 34 so as to force this mixture down into the annular chamber 19. The pressure is continually applied to the mixture 34 until the bonding mixture appears at the outlet opening 26. The bonding mixture is viscous by reason of the powdered asbestos therein and tends to hold a pressure within the annular chamber 19 for a period of time after air pressure is interrupted. The pres- 3 sure thus applied to the bonding mixture is suicient to slightly enlarge the chamber 19. t

Immediately after the annular chamber 19 is completely filled, the clamps 30 and the filling apparatus are removed from thev tank and each end of thetank is fitted with a spring clamp 36 having plugs 37 adapted to enter the openingsrZS and 26 in the wall of the tubular section 11. This -is accomplished before the Viscous bonding material 34 losesthe pressure applied thereto during the filling of the annular chamber 19'. Thus as the clamp 36 is applied, the pressure on the bonding material 3'4 is retained. With each end of the tank equipped with a spring clamp 36 and the bonding material being retained under pressure thereby, the assembly is placed in an oven and cured so that the bonding material polymerizes while 4under pressure. Expansion of the chamber 19 during the application of pressure to the bonding mixture and the expansion of the bonding mixture at the start of the curing operation presses the Walls of the chamber 19 outwardly. The resilience of the walls of the chamber 19 results in a chamber that gets smaller as permitted by the shrinkage of the bonding material upon polymerization. Thus the parts of the cap and the tubular body resume their original unstressed condition after the curing of the bonding mixture and the shrinkage thereof.

As the chamber 19 is restored toY its original dimensions, the walls thereof maintain firm. contact with the bonding material. The interlocking grooves in the annular chamber are filled with bonding material and the bonding material forms a solid locking ringV of annular shape which Yeffectively prevents separation of the end caps from the tubular portion of the tank under pressure. The end caps 14 and 15 in the tank 10 as illustrated are convex. yThose skilled in the art will appreciate that one or both caps may be made concave depending upon the particular use frwhich the tankis designed. lt will also be. understood that .the method andvapparatus employed herein'for bonding end caps to a tank may be utilized for securing other tubular structures, such as fiber glass pipe sections, to each other.

The term bonding/mixture. or bonding material as used herein includes-'resins and catalysts other. than the polyester lresin and the MBK peroxide catalyst specifically described herein. "We contemplate that resins such as epoxy resins andl phenolic resins may be employed as bonding materials. Although We have described: a tank according to our invention `in considerable detail, numerous modifications may be made therein and in the methods and apparatus disclosed without departing from the scope of our invention as defined in the following claims.

What is claimed is:

1. In combination, first `and second curedv resin-bonded fiberglass members respectively lhaving outer and inner cylindrical portions which interlit in telescopingengagement with one another, the inner cylindrical portion having an interference t with the outer cylindrical portion drical portion dening between them a circumferentially and axially continuous annular space extending from one of said interference fit locations to the other, said members presenting at said annular space confronting cylindrical faces each having substantial surface depressions therein, and solidified bonding vmaterial filling said annular space and filling said surface depressions and bonded at a pair of locations spaced apart a substantial distance axially, said inner cylindrical portion hvingra cylindrical groove formed thereon extending with substantially uniform depth between said pair of interference fit locations and defining with said outer cylindrical portion a circumferentially and axially continuous. annular space extending from one of saidV interference fit locations to they other, said member presenting at said annular space confronting cylindrical faces each having substantial surface depressions therein and solidified Vbonding material filling said` annular space and `filling said surface depressions and bonded to both of said members.

3. In combination, first and second cured resin bonded fiber glass members respectively having outer and inner cylindrical portions which interfit in telescoping engagement with one another, the inner cylindrical portion havat a pairof locations spaced aparta substantial distance' axial-ly, said interftting portionsV having an offset cylining an inter-ference fit with the outer cylindrical portion at a pair of locations spaced apart a substantial distance axially, said interfitting portions having an offset cylindrical portion defining betweenk them a circumferentially and axially continuous annular space extending from one of said interference fit locations to the other, said members presenting at said annular space confronting cylindrical faces, each of said confronting cylindrical faces having threaded groovesA thereon, and solidified bonding material filling saidV annular space and filling said threaded grooves and bonded to both of said members.

References Cited in the file of this patent UNITED STATES PATENTS 1,955,872 Cosgrove Apr. 24, '1934 2,347,309' Zoldok Apr. 25, 1944 2,388,042 Daily Oct. 30, ,1'945 f 2,392,734 Habersturnp lan; 8, 1946 2,541,371 Kops Feb. 13,1951

2,576,392 Downs Nov. 27, 1951 2,601,266 Ducatman et al.V June 24, 1952 2,632,577 Sacco Mar. 24, 1953y 2,716,623 Tator Aug.L 30, 19'5'5 2,739,917 Schulze Mar. 27; 1956 2,785,910 Munger Mar. v19', 1957 2,876,154 Usab Mar. 3, 1959 2,892,749 Carpenter June 30, 1959 2,977,268 Randolph Mal". 28, 1961 2,977,269

Nerwick Mar. 28, 1961 

1. IN COMBINATION, FIRST AND SECOND CURED RESIN-BONDED FIBERS GLASS MEMBER REPECTIVELY HAVING OUTER AND INNER CYLINDRICAL PORTIONS WHICH INTERFIT IN TELESCOPING ENGAGEMENT WITH ONE ANOTHER, THE INNER CYLINDRICAL PORTION HAVING AN INTERFERENCE FIT WITH THE OUTER CYLINDRICAL PORTION AT A PAIR OF LOCATIONS SPACED APART A SUBSYANTIAL DISTANCE AXIALLY, SAID INTERFITTING PORTIONS HAVING AN OFFSET CYLINDRICAL PORTION DEFINING BETWEEN THEM A CIRCUMFERENTIALLY AMD AXIALLY CONTINUOUS ANNULAR SPACE EXTENDING FROM ONE OF SAID INTERFERENCE FIT LOCATIONS TO THE OTHER, SAID MEMBERS PRESENTING AT SAID ANNULAR SPACE CONFRONTING CYLINDRICAL FACES EACH HAVING SUBSTANTIAL SURFACE DEPRESSIONS THEREIN, AND SOLIDFIED BONDING MATERIAL FILLING SAID ANNULAR SPACE AND FILLING SAID SURFACE DEPRESSION AND BONDED TO BOTH SAID MEMBERS. 